VB.net：使用共享方法获取数据库连接有任何问题吗？
我有一个实用程序类来创建 &返回数据库连接：
Public Shared Function GetConnection() as OracleConnection
dim c as New OracleConnection()
... set connection string...
c.Open()
Return c
End Function
并发调用返回相同连接是否存在风险？连接字符串启用池化。
I have a utility class that creates & returns a db connection:
Public Shared Function GetConnection() as OracleConnection
dim c as New OracleConnection()
... set connection string...
c.Open()
Return c
End Function
Is there any risk of concurrent calls returning the same connection? The connection string enables pooling.
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我不这么认为。
由于 c 是一个局部变量（“堆栈变量”）而不是静态变量，因此每次调用都有它自己的 c 实例。
接下来，您创建一个新对象（连接）并返回它。
I don't think so.
Since c is a local variable ("stack variable") and not a static one every call has it's own instance of c.
Next you create a new object (the connection) and return this.
并发性不应该有任何问题，因为每次调用都是一个新连接。
不过，我可能会做出一项更改：将方法设为
私有。这将迫使您将所有数据访问代码放在一个类中，并推动创建一个漂亮的、独立的数据访问层。至少将其设置为
内部，以便您的数据访问层仅限于单个程序集（与代码的其余部分分开）。Shouldn't be any problem with concurrency, because each call is a new connection.
I might make one change, though: make the method
private.This will force you to put all your data access code in one class and push to create a nice, separate data access layer. At very least make it
internalso that your data access layer is confined to a single assembly (that's separate from the rest of your code).由于您每次都会返回一个新连接，因此不会出现任何并发问题。如果您使用
Shared方法返回对同一个实例的多个引用，这可能是一个问题，但这不是您在这里所做的。只要每次总是返回数据库连接对象的新实例，就可以安全地以这种方式使用此方法。任何连接池也将像往常一样工作 - 您也无需担心您的
Shared方法使用在那里产生的问题。Since you are returning a new connection each time you will not have any concurrency issues. If you were using a
Sharedmethod to return multiple references to the same instance, that could be a problem but that is not what you are doing here.You are safe to use this method in this way as long as you are always returning a new instance of your database connection object each time. Any connection pooling will also work the same as it always would - you won't need to worry about your
Sharedmethod usage created problems there either.暂时忘记并发调用问题。如果存在任何连接池，您绝对可以重用相同的底层数据库连接，即使它们不使用相同的对象。
这通常是一件可取的事情，因为打开与数据库的连接可能是一项昂贵的操作。
您是否担心从另一个调用者那里关闭连接对象？如果是这样，正如另一个回复指出的那样，我认为您提供的代码是安全的。
Forget the concurrent calls issue for a moment. If there is any connection pooling going on you will absolutely have reuse of the same underlying database connections, even if they don't use the same object.
This is generally a desirable thing as opening a connection to the DB can be an expensive operation.
Are you worried about closing the connection object out from under another caller? If so, as another response pointed out, I think you are safe with the code you provided.